Ventilated Drainage System

ABSTRACT

A method and apparatus for draining fluid from a structure on an aircraft. The apparatus comprises a drainage tube, a housing, a number of inlet holes in the housing, and a number of outlet holes in the housing. The drainage tube has first end that connects to a structure on an aircraft and a second end opposite the first end. The housing connects to the structure. The drainage tube is located within the housing. Air flows into the housing during flight of the aircraft through the number of inlet holes in the housing. The air flows out of the housing during flight of the aircraft through the number of outlet holes. The air flowing into the housing through the number of inlet holes and out the housing through the number of outlet holes directs fluid out of the drainage tube and away from the structure during flight of the aircraft.

BACKGROUND INFORMATION

1. Field

The present disclosure relates generally to draining fluids and, inparticular, to draining fluids from a structure on a mobile platform.Still more particularly, the present disclosure relates to a method andapparatus for draining fluid away from the structure during variousstages of operation of the mobile platform.

2. Background

Drainage systems are often used to drain fluids from mobile platforms.For example, a drainage system may be used to drain fluids from anaircraft during operation of the aircraft. A drainage system may be usedto drain leaking fuel, hydraulic fluid, water, or other types of fluidsfrom the structure. These drainage systems are employed to dispose ofunneeded fluids and prevent undesired contact between the drained fluidsand the mobile platform.

Some drainage systems include a drainage tube extending from the outersurface of the structure. The length, size, and shape of the drainagetube may be altered to modify the amount of fluid drained from the tube.For instance, the size of an opening in the tube may be increased toincrease the amount of fluid drained from the tube. Gravity causes thefluid to flow out of the structure, through the drainage tube, and intothe environment surrounding the mobile platform.

During movement, the forward motion of the mobile platform may force thefluid draining from the drainage tube back onto the structure. Contactbetween the drained fluid and the mobile platform may be undesirable insome instances. For example, re-entry of fluids into an aircraft enginemay degrade performance of the engine. Some fluids may causeinconsistencies in the paint on the structure. These inconsistencies mayreduce the aesthetics of the structure and may result in repainting ofportions of the structure.

To prevent fluid from being forced back onto the mobile platform duringflight, the drainage tube may be lengthened to provide a desireddrainage path for the fluid. Shields also may be placed over thedrainage tube to reduce back splatter of the fluid onto the mobileplatform. These modifications, however, may increase the weight of thedrainage system more than desired and increase the drag of the mobileplatform.

Further, longer drainage systems may not provide a desired level ofclearance above the ground as the mobile platform moves on the ground.Therefore, it would be desirable to have a method and apparatus thattake into account at least some of the issues discussed above, as wellas other possible issues.

SUMMARY

In one illustrative embodiment, an apparatus comprises a drainage tube,a housing, a number of inlet holes in the housing, and a number ofoutlet holes in the housing. The drainage tube has first end thatconnects to a structure on a mobile platform and a second end oppositethe first end. The housing also connects to the structure. The drainagetube is located within the housing. Air flows into the housing, duringmovement of the mobile platform, through the number of inlet holes inthe housing. The air flows out of the housing, during the movement ofthe mobile platform, through the number of outlet holes. The air flowinginto the housing through the number of inlet holes and out of thehousing through the number of outlet holes directs fluid out of thedrainage tube and away from the structure during the movement of theaircraft.

In another illustrative embodiment, a method of draining fluid from astructure on a mobile platform is provided. Air moves through a numberof inlet holes into a housing of a drainage system connected to thestructure. The air circulates within the housing. The air moves througha number of outlet holes in the housing. The fluid drains from adrainage tube located in the housing. The air flowing into the housingthrough the number of inlet holes and out the housing through the numberof outlet holes directs the fluid out of the drainage tube and away fromthe structure during movement of the mobile platform.

In yet another illustrative embodiment, a drainage system for astructure on an aircraft comprises a drainage tube, a housing, a numberof inlet holes, and a number of outlet holes. The drainage tube isphysically associated with the structure. The drainage tube drains afluid from the structure. The housing is physically associated with thestructure. The drainage tube is located within the housing. The numberof inlet holes is located on a leading edge of the housing. Air flowsinto the housing through the number of inlet holes during flight of theaircraft. The air flows out of the housing during flight of the aircraftthrough the number of outlet holes. The air flowing into the housingthrough the number of inlet holes and out of the housing through thenumber of outlet holes directs the fluid out of the drainage tube andaway from the structure such that splatter of the fluid on the aircraftis reduced.

The features and functions can be achieved independently in variousembodiments of the present disclosure or may be combined in yet otherembodiments in which further details can be seen with reference to thefollowing description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the illustrativeembodiments are set forth in the appended claims. The illustrativeembodiments, however, as well as a preferred mode of use, furtherobjectives and features thereof, will best be understood by reference tothe following detailed description of an illustrative embodiment of thepresent disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is an illustration of an aircraft in accordance with anillustrative embodiment;

FIG. 2 is an illustration of a block diagram of a drainage environmentin accordance with an illustrative embodiment;

FIG. 3 is an illustration of a drainage system on a nacelle for anaircraft engine in accordance with an illustrative embodiment;

FIG. 4 is an illustration of a drainage system for a nacelle inaccordance with an illustrative embodiment;

FIG. 5 is an illustration of a cross-sectional view of a drainage systemfor a nacelle in accordance with an illustrative embodiment;

FIG. 6 is an illustration of a side view of a drainage system for anacelle in accordance with an illustrative embodiment;

FIG. 7 is an illustration of air flowing within a housing of a drainagesystem during flight of an aircraft at a first speed in accordance withan illustrative embodiment;

FIG. 8 is an illustration of air flowing within a housing of a drainagesystem during flight of an aircraft at a second speed in accordance withan illustrative embodiment;

FIG. 9 is an illustration of a front view of a drainage system for anacelle in accordance with an illustrative embodiment;

FIG. 10 is an illustration of air flowing out of a housing of a drainagesystem during flight of an aircraft at a first speed in accordance withan illustrative embodiment;

FIG. 11 is an illustration of air flowing out of a housing of a drainagesystem during flight of an aircraft at a second speed in accordance withan illustrative embodiment;

FIG. 12 is an illustration of an enlarged view of a drainage system withtwo drainage tubes in accordance with an illustrative embodiment;

FIG. 13 is an illustration of a flowchart of a process for drainingfluid from a structure on a mobile platform in accordance with anillustrative embodiment;

FIG. 14 is an illustration of a flowchart of a process for forming adrainage system for a structure in accordance with an illustrativeembodiment;

FIG. 15 is an illustration of a block diagram of an aircraftmanufacturing and service method in accordance with an illustrativeembodiment; and

FIG. 16 is an illustration of a block diagram of an aircraft in which anillustrative embodiment may be implemented.

DETAILED DESCRIPTION

The illustrative embodiments recognize and take into account one or moredifferent considerations. For example, the illustrative embodimentsrecognize and take into account that it may be desirable to have adrainage system for a mobile platform that reduces splatter of drainedfluid back onto the mobile platform. This mobile platform may be, forexample, without limitation, an aircraft. The illustrative embodimentsrecognize and take into account that the drainage system must reducethis back splatter to within selected tolerances in order to passvarious drainage certification tests for the mobile platform. A faileddrainage certification test results in costly rework and modification ofthe drainage system to achieve compliance with certificationrequirements.

The illustrative embodiments recognize and take into account thatcompliance with certification requirements often requires manufacturersto lengthen the drainage system to ensure the fluid flows away from themobile platform in a desired manner. However, making such modificationsto the drainage system increases the overall weight and complexity ofthe mobile platform. The illustrative embodiments further recognize andtake into account that adding heavy components to the drainage tube orlengthening the drainage tube increases drag, which reduces the overallaerodynamic performance of the mobile platform.

In addition, the illustrative embodiments recognize and take intoaccount that lengthening the drainage system to prevent back splattermay not be feasible in some instances. For example, a lengtheneddrainage tube may scrape the ground during operation of the mobileplatform, contact objects underneath the aircraft during groundoperation, or both. As an example, when the mobile platform is anaircraft, a lengthened tube may scrape the ground during takeoff.

Thus, the illustrative embodiments provide a method and apparatus fordraining fluid from a structure on a mobile platform. An apparatuscomprises a drainage tube, a housing, a number of inlet holes in thehousing, and a number of outlet holes in the housing. The drainage tubehas a first end that connects to the structure on the mobile platformand a second end having an opening. The housing also connects to thestructure. The drainage tube is located within the housing. Air flowsinto the housing during movement of the mobile platform through thenumber of inlet holes in the housing. The air flows out of the housingduring the movement of the mobile platform through the number of outletholes. The air flowing into the housing through the number of inletholes, through the housing, and out of the housing through the number ofoutlet holes directs fluid out of the drainage tube and away from thestructure during the movement of the mobile platform.

With reference now to the figures, and in particular, with reference toFIG. 1, an illustration of an aircraft is depicted in accordance with anillustrative embodiment. In this illustrative example, aircraft 100 haswing 102 and wing 104 attached to fuselage 106. Aircraft 100 includesengine 108 attached to wing 102 and engine 110 attached to wing 104.

Fuselage 106 has tail section 112. Horizontal stabilizer 114, horizontalstabilizer 116, and vertical stabilizer 118 are attached to tail section112 of fuselage 106.

Aircraft 100 is an example of a mobile platform in which a drainagesystem in accordance with an illustrative embodiment may be implementedto drain fluids. For example, drainage system 120 is used to drain fluidfrom engine 110 in aircraft 100. Drainage system 120 extending outwardfrom nacelle 122 of engine 110 is shown in section 124.

Turning next to FIG. 2, an illustration of a block diagram of a drainageenvironment is depicted in accordance with an illustrative embodiment.Drainage environment 200 is an example of an environment in whichdrainage system 202 is used to drain fluid 204 from structure 206.Drainage system 120 in FIG. 1 is an example of a physical implementationfor drainage system 202 shown in block form in this figure.

As depicted, drainage system 202 is connected to structure 206 toprevent fluid 204 from collecting in structure 206. In this illustrativeexample, fluid 204 is liquid that is unneeded for operation of structure206. For instance, fluid 204 may be fluid leaking from components withinstructure 206.

As another example, fluid 204 may be condensation formed on a surface ofstructure 206. In yet another illustrative example, fluid 204 may benormal fluid loss from a mechanical system housed within structure 206.Fluid 204 may comprise at least one of oil, water, a hydraulic fluid,fuel, a coolant, or some other type of fluid in this illustrativeexample.

As used herein, the phrase “at least one of,” when used with a list ofitems, means different combinations of one or more of the listed itemsmay be used and only one of the items in the list may be needed. Theitem may be a particular object, thing, or category. In other words, “atleast one of” means any combination of items or number of items may beused from the list, but not all of the items in the list may berequired.

For example, “at least one of item A, item B, and item C” may mean itemA; item A and item B; item B; item A, item B, and item C; or item B anditem C. In some cases, “at least one of item A, item B, and item C” maymean, for example, without limitation, two of item A, one of item B, andten of item C; four of item B and seven of item C; or some othersuitable combination.

It may be undesirable for fluid 204 to collect within structure 206. Forexample, fluid 204 within structure 206 may decrease the efficiency ofstructure 206, corrode structure 206, or otherwise become undesirable.

In this depicted example, structure 206 may take various forms. Forexample, without limitation, structure 206 may be selected from one of askin panel, a wing, a compartment, a tank, a drive system, a controlsurface, a nacelle, a power supply system, a wheel-well blister, awindow, a windshield, and other suitable types of structures.

As depicted, structure 206 is physically associated with mobile platform201. A first component, structure 206, is considered to be physicallyassociated with a second component, mobile platform 201, by beingsecured to the second component, bonded to the second component, mountedto the second component, welded to the second component, fastened to thesecond component, and/or connected to the second component in some othersuitable manner. The first component also may be connected to the secondcomponent using a third component. The first component may also beconsidered to be physically associated with the second component bybeing formed as part of the second component, an extension of the secondcomponent, or both.

In this depicted example, mobile platform 201 takes the form of aircraft208. Aircraft 100 shown in FIG. 1 is an example of a physicalimplementation of aircraft 208 shown in block form in this figure.

In other illustrative examples, however, mobile platform 201 may takeother forms. For example, without limitation, mobile platform 201 may bea surface ship, a tank, a personnel carrier, a train, an automobile, andother suitable platforms. In this manner, mobile platform 201 may be avehicle.

As illustrated, drainage system 202 extends outward from structure 206to drain fluid 204 from the interior of structure 206 into theenvironment around structure 206. Drainage system 202 comprises a numberof components. In this illustrative example, drainage system 202includes drainage tube 210 and housing 212. Drainage tube 210 is anobject that drains fluid 204 from structure 206.

As depicted, drainage tube 210 has first end 213, second end 214opposite first end 213, and channel 215. First end 213 of drainage tube210 has opening 216. Second end 214 of drainage tube 210 has opening218.

In this depicted example, first end 213 of drainage tube 210 isconnected to structure 206 on aircraft 208. Drainage tube 210 is influid communication with structure 206 at first end 213. Drainage tube210 is also in fluid communication with the environment surroundingstructure 206 at second end 214.

In an illustrative example, a component is in fluid communication withanother component when a fluid may flow from one component to anothercomponent. In this manner, fluid 204 flows from structure 206 throughopening 216 in first end 213 of drainage tube 210, through channel 215,and out opening 218 in second end 214. Gravity 220 causes fluid 204 toflow through drainage tube 210 in this manner.

When aircraft 208 is in flight, however, gravity 220 is insufficient todrain fluid 204 in a manner that prevents fluid 204 from contactingstructure 206, other portions of aircraft 208, or both. In other words,drainage path 221 of fluid 204 is not directed away from aircraft 208.

Instead, the forward motion of aircraft 208 during flight causessplatter 222 of fluid 204 back onto aircraft 208. In this illustrativeexample, splatter 222 refers to a splash of fluid 204 that contacts oneor more structures in aircraft 208. For example, splatter 222 occurswhen fluid 204 from drainage tube 210 splashes onto a skin panel inaircraft 208.

In an illustrative example, the forward motion of aircraft 208 duringflight also may cause re-entry 224 of fluid 204 into structure 206.Re-entry 224 of fluid 204 occurs when fluid 204 previously drained fromstructure 206 is re-ingested by structure 206. For instance, re-entry224 of fluid 204 occurs when fluid 204 previously drained from engine110 in FIG. 1 re-enters engine 110.

Both splatter 222 and re-entry 224 of fluid 204 are undesirable in thisillustrative example. At least one of splatter 222 or re-entry 224 offluid 204 may degrade performance of aircraft 208, corrode structure206, cause structure 206 to fail, or a combination thereof.

To reduce at least one of splatter 222 or re-entry 224 of fluid 204,housing 212 is placed over drainage tube 210 such that drainage tube 210is located within housing 212. Housing 212 is a structure that coversdrainage tube 210. In some cases, housing 212 may be referred to as ashield for drainage tube 210.

Housing 212 is connected to structure 206 in this illustrative example.In some cases, drainage tube 210 is physically associated with housing212.

As depicted, housing 212 includes number of inlet holes 226 and numberof outlet holes 228. As used herein, a “number of” items is one or moreitems. In this depicted example, number of inlet holes 226 includes oneor more inlet holes.

In an illustrative example, air 230 flows into housing 212 throughnumber of inlet holes 226 during flight of aircraft 208. Air 230circulates through housing 212 and flows out of housing 212 throughnumber of outlet holes 228. In this manner, number of inlet holes 226provides ventilation 232 for housing 212.

The addition of housing 212 to drainage tube 210 directs fluid 204 awayfrom aircraft 208 without lengthening drainage tube 210. Specifically,air 230 flowing into housing 212 through number of inlet holes 226 andout of housing 212 through number of outlet holes 228 directs fluid 204out of drainage tube 210 and away from structure 206 during flight ofaircraft 208. This flow of air 230 through housing 212 results indesired drainage path 233 for fluid 204. Desired drainage path 233 is apath for drainage of fluid 204 that reduces splatter 222 of fluid 204 onaircraft 208. Re-entry 224 of fluid 204 into structure 206 is alsoreduced or eliminated when fluid 204 has desired drainage path 233.

In this depicted example, housing 212 has shape 234. Shape 234 is aconfiguration for housing 212 that reduces drag on housing 212 duringflight of aircraft 208. In this manner, shape 234 is aerodynamic shape236 for housing 212.

As shown, housing 212 has leading edge 238 and trailing edge 240.Leading edge 238 is the portion of housing 212 that first contacts theair. In other words, leading edge 238 is the forward portion of housing212. Trailing edge 240 is the portion of housing 212 opposite leadingedge 238. In some illustrative examples, aerodynamic shape 236 ofhousing 212 may be formed such that leading edge 238 is wider thantrailing edge 240. Number of inlet holes 226 is located on leading edge238 of housing 212.

In an illustrative example, size 242 and shape 244 of number of inletholes 226, number of outlet holes 228, or both may be designed such thata desired amount of air 230, flow of air 230, or both travel throughhousing 212. For instance, size 242 of each of number of inlet holes 226may be increased to increase the amount of air 230 entering housing 212.In another illustrative example, size 242 of number of outlet holes 228may be reduced to increase the speed at which air 230 flows out ofhousing 212.

In a depicted example, size 242 refers to the dimensions of number ofinlet holes 226. For instance, size 242 may be the diameter of acircular hole. Shape 244 may be selected from one of a circular shape,an oblong shape, a hexagonal shape, a square shape, a rectangular shape,an irregular shape, or other suitable shapes.

In some illustrative examples, nozzle 246 may be connected to housing212. Nozzle 246 may cover number of outlet holes 228. Nozzle 246 is adevice that further directs fluid 204 and air 230 away from structure206. In an illustrative example, nozzle 246 provides more precisedirection of fluid 204 and air 230 than open outlet holes.

Housing 212 is configured to direct fluid 204 away from aircraft 208without adding undesired weight to aircraft 208. For example, housing212 may be formed from lighter weight materials than some currently usedsystems. These materials may include, for example, without limitation,composite material, aluminum, titanium, corrosion resistant steel, andother suitable materials. Lightweight materials may be selected forhousing 212 since housing 212 does not need to withstand external loads.Housing 212 encounters only aero loads in this illustrative example.

The illustration of drainage system 202 in FIG. 2 is not meant to implyphysical or architectural limitations to the manner in which anillustrative embodiment may be implemented. Other components in additionto or in place of the ones illustrated may be used. Some components maybe optional. Also, the blocks are presented to illustrate somefunctional components. One or more of these blocks may be combined,divided, or combined and divided into different blocks when implementedin an illustrative embodiment.

For example, drainage system 202 may include more than one drainagetube. In this case, drainage tube 210 is a first drainage tube. A seconddrainage tube also may be located within housing 212. The seconddrainage tube may drain fluid 204 from structure 206, structuresadjacent to structure 206, or a combination thereof.

Further, although the illustrative embodiments are described withrespect to mobile platform 201, and specifically aircraft 208, anillustrative embodiment may be implemented in other platforms that havefluid drainage concerns. The fluid dynamics of an illustrativeembodiment are operable to prevent back splatter and re-entry as long asfluid flows through the inlet holes and out of the outlet holes.

With reference now to FIG. 3, an illustration of a drainage system on anacelle for an aircraft engine is depicted in accordance with anillustrative embodiment. Section 124 with drainage system 120 extendingoutward from nacelle 122 for engine 110 of aircraft 100 from FIG. 1 isshown in this view. Engine 110 is an example of a physicalimplementation for structure 206 shown in block form in FIG. 2.

As shown, drainage system 120 includes housing 300 and drainage tube 302located within housing 300. Housing 300 is connected to nacelle 122. Inthis illustrative example, housing 300 and drainage tube 302 arephysically associated with nacelle 122. Housing 300 has inlet holes 304and outlet hole 306.

Inlet holes 304 are located on leading edge 307 of housing 300 in thisillustrative example. Specifically, inlet holes 304 are located on thelower half of leading edge 307. Trailing edge 308 is located oppositeleading edge 307.

In an illustrative example, air 310 enters housing 300 through inletholes 304 and exits housing 300 through outlet hole 306. In this manner,air 310 circulates within housing 300 during flight of aircraft 100.

In FIG. 4, an illustration of a drainage system for a nacelle isdepicted in accordance with an illustrative embodiment. In this depictedexample, an enlarged bottom view of drainage system 120 is shown in thedirection of lines 4-4 in FIG. 3.

As illustrated, a portion of drainage tube 302 extends through outlethole 306. In this illustrative example, end 400 of drainage tube 302 issubstantially flush with bottom surface 402 of housing 300. In otherillustrative examples, end 400 of drainage tube 302 may extend slightlyoutward from bottom surface 402 of housing 300 or may be shorter thanhousing 300, depending on the particular implementation. In otherillustrative examples, bottom surface 402 may be omitted from the designof housing 300.

In this illustrative example, drainage tube 302 has opening 404. Fluiddrains from drainage tube 302 through opening 404.

As shown, housing 300 of drainage system 120 has aerodynamic shape 406.Aerodynamic shape 406 is designed such that leading edge 307 of housing300 is wider than trailing edge 308 of housing 300. The width of housing300 tapers in the direction of trailing edge 308 to reduce drag onhousing 300.

Referring next to FIG. 5, an illustration of a cross-sectional view of adrainage system for a nacelle is depicted in accordance with anillustrative embodiment. In this illustration, a cross-sectional view ofdrainage system 120 taken along lines 5-5 in FIG. 4 is shown.

Chamber 500 is seen in this view. Chamber 500 is a space within housing300 that surrounds drainage tube 302. Air 310 as shown in FIG. 3circulates through chamber 500 in this illustrative example.

Turning now to FIG. 6, an illustration of a side view of a drainagesystem for a nacelle is depicted in accordance with an illustrativeembodiment. In this depicted example, a side view of drainage system 120is shown in the direction of lines 6-6 in FIG. 3. Housing 300 is shownin phantom such that drainage tube 302 is seen in greater detail.

As illustrated, end 600 of drainage tube 302 is connected to nacelle122. End 600 also has an opening (not shown in this view) through whichfluid 602 flows. Fluid 602 flows from end 600, through drainage tube302, and out opening 404 into the environment around nacelle 122.

When aircraft 100 is not in flight, drainage tube 302 drains fluid 602out of nacelle 122 in the direction of arrow 604. Gravity assists indraining fluid 602. As aircraft 100 picks up speed, gravity isinsufficient to prevent fluid 602 from splattering back on nacelle 122or re-entering nacelle 122. The air flowing from housing 300 reducessuch splatter and re-entry to fall within selected tolerances.

FIGS. 7-8 show illustrations of air 310 flowing within housing 300 ofdrainage system 120 from FIG. 6 during flight of an aircraft atdifferent speeds. FIGS. 7-8 also depict the drainage path for fluid 602directed by the flow of air 310 exiting housing 300. These figures showsome examples of the path of air 310 flowing inside of housing 300. Inparticular, air 310 circulates through housing 300 and out of housing300 in the direction of arrow 704.

In FIG. 7, aircraft 100 is traveling in the direction of arrow 706 at afirst speed. Air 310 flows into housing 300 through inlet holes 304 andcirculates within chamber 500, shown in FIG. 5, in housing 300. Aportion of air 310 then flows out of housing 300 through outlet hole306. The flow of air 310 directs fluid 602 away from nacelle 122 toreduce or eliminate splatter or re-entry. Drainage path 708 of fluid 602is shown in this view along with ventilation from air 310.

In FIG. 8, aircraft 100 is traveling in the direction of arrow 706 at asecond speed that is faster than the speed of aircraft 100 shown in FIG.7. Fluid 602 has drainage path 800 in this illustrative example. Air 310flowing out of housing 300 through outlet hole 306 directs fluid 602away from nacelle 122 along drainage path 800. In this manner, drainagesystem 120 reduces or eliminates splatter and re-entry of fluid atvarious speeds of aircraft 100.

Turning next to FIG. 9, an illustration of a front view of a drainagesystem for a nacelle is depicted in accordance with an illustrativeembodiment. As illustrated, a front view of drainage system 120 is shownin the direction of lines 9-9 in FIG. 3. The size and shape of inletholes 304 is shown in this view.

As shown, adjacent inlet holes 304 are located equidistant from oneanother. In addition, each of inlet holes 304 has the same shape. Inother examples, inlet holes 304 may have different shapes and locationson leading edge 307. Inlet holes 304 intercept a high total pressure inthis illustrative example.

FIGS. 10-11 are illustrations of drainage system 120 as shown in FIG. 9.FIGS. 10-11 show air 310 flowing out of housing 300 of drainage system120 during flight of aircraft 100 at different speeds. FIGS. 10-11 alsodepict the manner in which fluid 602 flows out of drainage tube 302 andaway from nacelle 122.

In FIG. 10, aircraft 100 is again traveling at the slower speed. Theflow of air 310 out of housing 300 first directs fluid 602 downwardbefore fluid 602 is expelled in the opposite direction of travel ofaircraft 100. Even at a higher speed, as shown in FIG. 11, fluid 602 isdirected downward and away from nacelle 122 as air 310 flows throughhousing 300 from inlet holes 304 and out of outlet hole 306.

With reference next to FIG. 12, an illustration of an enlarged view of adrainage system with two drainage tubes is depicted in accordance withan illustrative embodiment. In this illustrative example, an enlargedview of drainage system 1200 is shown. Drainage system 1200 is anexample of an implementation for drainage system 202 attached to anaircraft structure shown in block form in FIG. 2.

As depicted, drainage system 1200 includes housing 1202, drainage tube1204, and drainage tube 1206. Drainage tube 1204 has opening 1208 anddrainage tube 1206 has opening 1210. In this depicted example, drainagetube 1204 and drainage tube 1206 drain fluid (not shown in this view)from one or more aircraft structures.

Housing 1202 of drainage system 1200 has inlet holes 1212, outlet hole1213, and outlet hole 1214 in this illustrative example. Air 1216 flowsinto housing 1202 through inlet holes 1212 and out of housing 1202through outlet hole 1213 and outlet hole 1214.

In an illustrative example, air 1216 flowing out of outlet hole 1213directs fluid draining from drainage tube 1204 away from the aircraft.In a similar fashion, air 1216 flowing out of outlet hole 1214 directsfluid draining from drainage tube 1206 away from the aircraft. In thismanner, housing 1202 reduces or eliminates splatter of the fluid backonto the aircraft, re-entry of the fluid into aircraft structures, orboth.

Although two outlet holes are shown in this illustrative example, othernumbers of outlet holes may be present in an illustrative embodiment.For example, without limitation, three holes, five holes, ten holes, orsome other suitable number of outlet holes may be present in housing1202.

Further, in another illustrative example, drainage tube 1204 anddrainage tube 1206 may share the same outlet hole. In this case, asingle outlet hole may have an oblong shape. In yet another illustrativeexample, the entire bottom portion of housing 1202 may be open.

The illustrations of drainage system 120 and drainage system 1200 inFIG. 1 and FIGS. 3-12 are not meant to imply physical or architecturallimitations to the manner in which an illustrative embodiment may beimplemented. Other components in addition to or in place of the onesillustrated may be used. Some components may be optional.

The different components shown in FIG. 1 and FIGS. 3-12 may beillustrative examples of how components shown in block form in FIG. 2can be implemented as physical structures. Additionally, some of thecomponents in FIG. 1 and FIGS. 3-12 may be combined with components inFIG. 2, used with components in FIG. 2, or a combination of the two.

With reference now to FIG. 13, an illustration of a flowchart of aprocess for draining fluid from a structure on an aircraft is depictedin accordance with an illustrative embodiment. The process illustratedin FIG. 13 may be implemented using drainage system 202 for structure206 during flight of aircraft 208 in FIG. 2.

The process begins by moving air through a number of inlet holes into ahousing of a drainage system connected to the structure such that theair circulates within the housing (operation 1300). Next, the processmoves the air through a number of outlet holes in the housing (operation1302).

The process then drains the fluid from a drainage tube located in thehousing such that the air flowing into the housing through the number ofinlet holes and out the housing through the number of outlet holesdirects the fluid out of the drainage tube and away from the structureduring flight of the aircraft (operation 1304), with the processterminating thereafter. During operation 1304, fluid may be drained fromone or more drainage tubes at substantially the same time. The airflowing out of the number of outlet holes directs the flow of fluid fromeach tube.

Turning to FIG. 14, an illustration of a flowchart of a process forforming a drainage system for a nacelle is depicted in accordance withan illustrative embodiment. The process illustrated in FIG. 14 may beimplemented to form drainage system 202 for a nacelle in aircraft 208 inFIG. 2.

The process begins by forming a housing for a drainage system having anaerodynamic shape (operation 1400). Next, the process forms a number ofinlet holes in a leading edge of the housing (operation 1402). Theprocess then forms a number of outlet holes in the housing (operation1404).

Thereafter, the process fits a nozzle over the number of outlet holes(operation 1406). In some cases, operation 1406 may be optional.

The process then positions the housing over a drainage tube (operation1408), with the process terminating thereafter. In operation 1408, thehousing may be retrofitted over an existing drainage tube on anaircraft. For instance, the housing may be formed and then positionedover an existing nacelle drainage tube. As another example, the housingmay be formed and then added to an existing drainage provision for awheel-well blister in an aircraft.

Alternatively, the housing and the drainage tube may be formed in onepiece. In this case, the drainage system is connected to the aircraft ina single step.

The flowcharts and block diagrams in the different depicted embodimentsillustrate the architecture, functionality, and operation of somepossible implementations of apparatuses and methods in an illustrativeembodiment. In this regard, each block in the flowcharts or blockdiagrams may represent at least one of module, a segment, a function, ora portion a combination thereof of an operation or step.

In some alternative implementations of an illustrative embodiment, thefunction or functions noted in the blocks may occur out of the ordernoted in the figures. For example, in some cases, two blocks shown insuccession may be executed substantially concurrently, or the blocks maysometimes be performed in the reverse order, depending upon thefunctionality involved. Also, other blocks may be added in addition tothe illustrated blocks in a flowchart or block diagram.

The illustrative embodiments of the disclosure may be described in thecontext of aircraft manufacturing and service method 1500 as shown inFIG. 15 and aircraft 1600 as shown in FIG. 16. Turning first to FIG. 15,an illustration of a block diagram of an aircraft manufacturing andservice method is depicted in accordance with an illustrativeembodiment. During pre-production, aircraft manufacturing and servicemethod 1500 may include specification and design 1502 of aircraft 1600in FIG. 16 and material procurement 1504.

During production, component and subassembly manufacturing 1506 andsystem integration 1508 of aircraft 1600 in FIG. 16 takes place.Thereafter, aircraft 1600 in FIG. 16 may go through certification anddelivery 1510 in order to be placed in service 1512. While in service1512 by a customer, aircraft 1600 in FIG. 16 is scheduled for routinemaintenance and service 1514, which may include modification,reconfiguration, refurbishment, and other maintenance or service.

Each of the processes of aircraft manufacturing and service method 1500may be performed or carried out by a system integrator, a third party,an operator, or a combination thereof. In these examples, the operatormay be a customer. For the purposes of this description, a systemintegrator may include, without limitation, any number of aircraftmanufacturers and major-system subcontractors; a third party mayinclude, without limitation, any number of vendors, subcontractors, andsuppliers; and an operator may be an airline, a leasing company, amilitary entity, a service organization, and so on.

With reference now to FIG. 16, an illustration of a block diagram of anaircraft is depicted in which an illustrative embodiment may beimplemented. In this example, aircraft 1600 is produced by aircraftmanufacturing and service method 1500 in FIG. 15 and may includeairframe 1602 with plurality of systems 1604 and interior 1606. Examplesof systems 1604 include one or more of propulsion system 1608,electrical system 1610, hydraulic system 1612, and environmental system1614. Any number of other systems may be included. Although an aerospaceexample is shown, different illustrative embodiments may be applied toother industries, such as the automotive industry.

Apparatuses and methods embodied herein may be employed during at leastone of the stages of aircraft manufacturing and service method 1500 inFIG. 15. In particular, drainage system 202 from FIG. 2 may be usedduring any one of the stages of aircraft manufacturing and servicemethod 1500. For example, without limitation, one or more components indrainage system 202 may be manufactured, assembled, and installed inaircraft 1600 during at least one of component and subassemblymanufacturing 1506, system integration 1508, or routine maintenance andservice 1514. Drainage system 202 may be used to drain fluid 204 fromaircraft 1600 while in service 1512. In addition, the effectiveness ofdrainage system 202 may be tested during certification and delivery 1510or some other stage of aircraft manufacturing and service method 1500.

In one illustrative example, components or subassemblies produced incomponent and subassembly manufacturing 1506 in FIG. 15 may befabricated or manufactured in a manner similar to components orsubassemblies produced while aircraft 1600 is in service 1512 in FIG.15. As yet another example, one or more apparatus embodiments, methodembodiments, or a combination thereof may be utilized during productionstages, such as component and subassembly manufacturing 1506 and systemintegration 1508 in FIG. 15. One or more apparatus embodiments, methodembodiments, or a combination thereof may be utilized while aircraft1600 is in service 1512, during maintenance and service 1514 in FIG. 15,or a combination thereof. The use of a number of the differentillustrative embodiments may substantially expedite the assembly ofaircraft 1600, reduce the cost of aircraft 1600, or both.

Thus, the illustrative embodiments provide a method and apparatus fordraining fluid 204 from structure 206 during flight of aircraft 208. Anapparatus comprises drainage tube 210, housing 212, number of inletholes 226 in housing 212, and number of outlet holes 228 in housing 212.Drainage tube 210 has first end 213 that connects to structure 206 onaircraft 208 and second end 214 opposite first end 213. Housing 212 alsoconnects to structure 206. Drainage tube 210 is located within housing212. Air 230 flows into housing 212, during flight of aircraft 208,through number of inlet holes 226. Air 230 flows out of housing 212,during flight of aircraft 208, through number of outlet holes 228. Air230 flowing into housing 212 through number of inlet holes 226 and outof housing 212 through number of outlet holes 228 directs fluid 204 outof drainage tube 210 and away from structure 206 during flight ofaircraft 208 to prevent splatter 222 of fluid 204, re-entry 224 of fluid204 into structure 206, or both.

With the use of a ventilated housing surrounding a drainage tube,unneeded fluid may be drained from the aircraft without the risk of backsplatter onto aircraft surfaces or re-entry of the drained fluid intothe structure. Moreover, the addition of a ventilated housing to acurrently installed drainage tube allows the drainage provisions to comeinto compliance with drainage certification standards without addingundesired weight and complexity to the aircraft. The housing can beformed from lightweight, relatively inexpensive materials. Further,addition of the housing will not impede the function of the drainagetube when the aircraft is static. In this manner, an existing drainagetube and drainage system needs no modification other than the additionof the ventilated housing. As a result, costly rework and replacement ofdrainage provisions on an aircraft may be avoided.

The illustrative embodiments also provide a solution to reduce oreliminate back splatter and re-entry without lengthening the drainageprovision. As a result, the illustrative embodiments save space and maybe used effectively in areas of the aircraft with clearance constraints.

The description of the different illustrative embodiments has beenpresented for purposes of illustration and description, and is notintended to be exhaustive or limited to the embodiments in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, different illustrativeembodiments may provide different features as compared to otherdesirable embodiments. The embodiment or embodiments selected are chosenand described in order to best explain the principles of theembodiments, the practical application, and to enable others of ordinaryskill in the art to understand the disclosure for various embodimentswith various modifications as are suited to the particular usecontemplated.

What is claimed is:
 1. An apparatus comprising: a drainage tube having afirst end that connects to a structure on a mobile platform and a secondend opposite the first end; a housing that connects to the structure,wherein the drainage tube is located within the housing; a number ofinlet holes in the housing though which air flows into the housingduring movement of the mobile platform; and a number of outlet holes inthe housing through which the air flows out of the housing during themovement of the mobile platform, wherein the air flowing into thehousing through the number of inlet holes and out of the housing throughthe number of outlet holes directs fluid out of the drainage tube andaway from the structure during the movement of the mobile platform. 2.The apparatus of claim 1, wherein the air flowing into the housingthrough the number of inlet holes and out of the housing through thenumber of outlet holes directs the fluid out of the drainage tube andaway from the structure such that splatter of the fluid on the mobileplatform is reduced.
 3. The apparatus of claim 1, wherein the drainagetube is a first drainage tube that drains the fluid from the structureand further comprising: a second drainage tube located within thehousing, wherein the second drainage tube drains the fluid from thestructure.
 4. The apparatus of claim 1 further comprising: a nozzleconnected to the housing and covering the number of outlet holes,wherein the nozzle directs the fluid draining from the drainage tubeaway from the structure.
 5. The apparatus of claim 1, wherein the numberof inlet holes is located on a leading edge of the housing.
 6. Theapparatus of claim 1, wherein the structure is selected from one of askin panel, a wing, a compartment, a tank, a drive system, a controlsurface, a nacelle, a power supply system, a wheel-well blister, awindow, and a windshield.
 7. The apparatus of claim 1, wherein thedrainage tube is physically associated with the housing.
 8. Theapparatus of claim 1, wherein the housing has a shape that reduces dragon the housing during the movement of the mobile platform.
 9. Theapparatus of claim 1, wherein the drainage tube and the housing form adrainage system for the structure that reduces re-entry of the fluidinto the structure.
 10. A method of draining fluid from a structure on amobile platform, the method comprising: moving air through a number ofinlet holes into a housing of a drainage system connected to thestructure, wherein the air circulates within the housing; moving the airthrough a number of outlet holes in the housing; and draining the fluidfrom a drainage tube located in the housing, wherein the air flowinginto the housing through the number of inlet holes and out the housingthrough the number of outlet holes directs the fluid out of the drainagetube and away from the structure during movement of the mobile platform.11. The method of claim 10, wherein moving the air into the housingthrough the number of inlet holes and out of the housing through thenumber of outlet holes directs the fluid out of the drainage tube andaway from the structure such that splatter of the fluid on the mobileplatform is reduced.
 12. The method of claim 10 further comprising:directing the fluid from the drainage tube through a nozzle connected tothe housing, wherein the fluid flows away from the structure.
 13. Themethod of claim 10, wherein the drainage tube is a first drainage tubeand further comprising: draining the fluid from a second drainage tubelocated in the housing.
 14. The method of claim 10 further comprising:forming the number of inlet holes in a leading edge of the housing. 15.The method of claim 10 further comprising: forming the housing with anaerodynamic shape configured to reduce drag on the housing during themovement of the mobile platform.
 16. A drainage system for a structureon an aircraft comprising: a drainage tube physically associated withthe structure that drains a fluid from the structure; a housingphysically associated with the structure, wherein the drainage tube islocated within the housing; a number of inlet holes located on a leadingedge of the housing, wherein air flows into the housing through thenumber of inlet holes during flight of the aircraft; and a number ofoutlet holes in the housing through which the air flows out of thehousing during the flight of the aircraft, wherein the air flowing intothe housing through the number of inlet holes and out of the housingthrough the number of outlet holes directs the fluid out of the drainagetube and away from the structure such that splatter of the fluid on theaircraft is reduced.
 17. The drainage system of claim 16, wherein thedrainage system reduces re-entry of the fluid into the structure. 18.The drainage system of claim 16 further comprising: a nozzle connectedto the housing, wherein the nozzle directs the fluid draining from thedrainage tube away from the structure.
 19. The drainage system of claim16, wherein the drainage tube is a first drainage tube and furthercomprising: a second drainage tube located within the housing, whereinthe second drainage tube drains the fluid from the structure.
 20. Thedrainage system of claim 16, wherein a shape of the number of inletholes is selected to provide a desired drainage path for the fluidduring the flight of the aircraft.